HUARUI 
Customized High Sealing Transformer Tanks
Our company can produce three mainstream oil-immersed transformer tank structures: Plate-Type Transformer Tanks, Corrugated Transformer Tanks, and Pad-Mounted Transformer Tanks. These are compatible with all voltage levels (10kV, 35kV, 110kV) and various oil-immersed transformers (30kVA to 120MVA), including off-load tap changers and on-load tap changers. They can be used for new transformer assembly, replacement of old tanks, equipment upgrades, and customized export projects. All three types of oil tanks comply with GB1094 and IEC60076 international manufacturing standards, integrating oil storage, load-bearing capacity, heat dissipation installation, outdoor protection, and sealing and leak-proofing. All tanks undergo multiple airtightness pressure tests before leaving the factory, making them suitable for various scenarios including domestic power grids, industrial and mining enterprises, photovoltaic and wind power energy storage, and overseas export power distribution projects.
Leakage is controlled through structural, welding, and pressure testing mechanisms, reducing subsequent maintenance and replenishment costs.
Prevents deformation and bulging during hoisting, transportation, and operation under hydraulic/vacuum conditions.
Suitable for complex operating conditions such as inland, coastal, chemical, and high-altitude environments.
Adaptable to different cooling methods, stabilizing transformer temperature rise.
Suitable for domestic projects and overseas exports.
Complete grounding and rounded corners eliminate installation and operation safety hazards.
| Applicable Voltage Levels | 10 kV, 35 kV, 110 kV full series of oil-immersed transformers |
| Capacity Range Covered | • Corrugated tank: 30 kVA ~ 2,500 kVA • Plate tank: 30 kVA ~ 120 MVA • American-style prefabricated tank: 30 kVA ~ 5,000 kVA (standard export capacity) |
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Optional Configurations |
1. Structure Type: Corrugated, bell-type, barrel-type, American-style integrated prefabricated tank; 2. Main Body Material: Q235-B carbon steel / Q345 high-strength steel / 304 stainless steel; 3. Cooling Method: ONAN natural air cooling, ONAF forced air cooling, ODAF forced oil circulation air cooling; 4. Sealing Solution: Ordinary EPDM seal, fluororubber oil-resistant seal; 5. Corrosion Resistance: Standard outdoor anti-corrosion coating, coastal heavy-duty anti-corrosion coating. |
Overview of Applicable Scenarios
10kV small and medium-sized distribution transformers, rural power grid upgrades, and built-in transformers in conventional prefabricated substations;
Plate-Type Oil Tanks
10kV large-capacity distribution transformers, 35kV/110kV substation main transformers, power plant step-up transformers, and large-scale new energy step-up substations;
American-Style Prefabricated Substation Oil Tanks
Pad-Mounted American-style transformers exported to North America, and compact urban outdoor landscape distribution projects;
General Needs
Transformer factory complete set matching, old oil tank replacement for power maintenance units, and equipment renovation and refurbishment.
1. Plate-Type Transformer Tank
Application Positioning
Mostly used in medium and large capacity distribution transformers and 35kV/110kV high-voltage main transformers, suitable for scenarios with large capacity, high voltage, high heat dissipation requirements, and high maintenance frequency.
Main Material Configuration
• Standard Material: Q235-B carbon steel plate, wall thickness 4～12mm; large-capacity high-voltage models use Q345 low-alloy high-strength steel plate; 304 stainless steel plate is optional for corrosive environments.
• Sealing: EPDM EPDM oil-resistant rubber gaskets; fluororubber seals are available for high-end applications, paired with hot-dip galvanized high-strength bolts.
Structural and Technological Advantages:
1. Single-piece bending molding provides extremely high rigidity, capable of withstanding vacuum negative pressure, internal oil pressure, and the impact of long-distance sea/land transport without deformation;
2. Two structures available: bell-shaped cover and integral barrel-shaped cover. The bell-shaped cover can be lifted as a whole, facilitating easy disassembly and maintenance of internal coils and cores; the barrel-shaped cover has fewer welds, reducing the risk of leakage;
3. Pre-installed flanges for external radiator installation on the tank wall, compatible with finned radiators, offering flexible heat dissipation expansion and adaptability to various cooling methods such as ONAN, ONAF, and ODAF;
4. Double-sided full welding of main welds; penetrant testing of critical welds; the cover flange uses a double-seal structure with a stop, combined with vacuum leak testing and nitrogen pressure testing, ensuring excellent oil leakage prevention performance;
5. Multi-layer anti-corrosion coating inside and out; the inner wall's oil-resistant and anti-corrosion coating does not contaminate transformer oil; the outer wall is weather-resistant and rust-proof, ensuring a long service life outdoors. Typical Applications: 10kV large-capacity distribution transformers, 35kV/110kV substation main transformers, power plant step-up transformers
2. Corrugated Transformer Tank
Application Positioning: Mainstream structure for small-capacity 10kV distribution transformers. Compact structure, no external heat sink required, suitable for compact prefabricated substations, community power distribution, and rural power grid upgrades.
Main Material Configuration: The main body is made of cold-rolled steel plate, bent and stamped into a corrugated wall, material Q235. The thickness design of the corrugated wall meets the elastic compensation requirements; equipped with oil-resistant sealing gaskets and galvanized fasteners.
Structural and Technological Advantages
1. One-piece stamped corrugated heat dissipation wall, utilizing corrugation to compensate for the thermal expansion and contraction of transformer oil, eliminating the need for an external oil conservator, resulting in a smaller overall size and footprint;
2. Fewer welds, integral welding, high production efficiency, and lower cost;
3. Simple structure, reliable sealing, passed factory airtightness test, and easy daily maintenance;
4. Neat and aesthetically pleasing appearance, suitable for mass production of standardized distribution transformers.
Typical Compatibility: 30kVA～2500kVA 10kV conventional distribution transformers, built-in distribution transformers in pad-mounted substations
3. American Pad-Mounted Transformer Tank
Application Positioning: Customized for American-style buried/outdoor pad-mounted distribution transformers, primarily used for North American export markets, urban landscape power distribution, and compact roadside distribution points in residential areas.
Main Material Configuration: Thickened Q235 steel plate, integrally sealed and welded, ensuring high overall strength; heavy-duty outdoor anti-corrosion coating, reinforced sealing structure design, suitable for long-term outdoor all-weather operation.
Structural and Technological Advantages:
1. Integral, fully sealed structure with a compact design, integrating fuses, tap changers, bushing compartments, and oil chambers within the same tank housing;
2. Fully enclosed protection, rainproof, dustproof, and impact-resistant, allowing for direct floor-mounted outdoor installation without a separate distribution room;
3. Internally reserved independent compartment structure, separating high and low voltage chambers, insulation layout matching UL and ANSI North American standards, meeting export certification requirements;
4. Upgraded anti-seepage sealing technology, suitable for outdoor environments with large temperature differences and high humidity, resulting in a longer maintenance-free period;
5. Standardized shape, dimensions conforming to American prefabricated substation installation specifications, suitable for overseas bulk export orders.
Typical Applications: Pad-Mounted American-style transformers exported to North America, outdoor compact municipal distribution transformers
1. Tank Base Material
Q235-B: Standard configuration, good welding performance, high cost-effectiveness, preferred for inland projects;
Q345 Low-alloy High-strength Steel: Large capacity, high voltage, export sea freight orders, stronger resistance to deformation;
304 Stainless Steel: Suitable for coastal salt spray and chemical corrosion environments, rust-proof, corrosion-resistant, and maintenance-free.
2. Sealing System
EPDM EPDM oil-resistant gasket (-40℃~150℃ oil and temperature resistant), high-end models use fluororubber sealant; flange gaps are fitted with oil-resistant sealant for secondary seepage prevention; all fasteners are hot-dip galvanized for rust and loosening prevention.
1. CNC Blanking and Bending: High dimensional accuracy, neat seams, and reduced welding defects;
2. Full Weld Seam Flaw Detection and Control: Critical welds are formed by argon arc welding/submerged arc welding, and penetrant testing is performed when necessary to check for cracks and porosity;
3. Double Sealing Structure for Flanges (Commonly Used in Plate-Type/American-Style Substations): Flange stop positioning + double-layer sealing gaskets to prevent localized oil leakage;
4. Three-Stage Airtightness Factory Inspection: ① Vacuum negative pressure leak detection and pressure holding ② Nitrogen positive pressure long-term pressure holding leak test ③ Oil injection to simulate temperature rise and re-inspect for leakage;
5. Multi-Layer Anti-Corrosion Coating: Internal and external sandblasting for rust removal, oil-resistant anti-corrosion coating on the inner wall, and a three-layer structure of epoxy zinc-rich primer + intermediate paint + weather-resistant topcoat on the outer wall; heavy-duty anti-corrosion thickened coating solutions can be customized for coastal areas.
6. Standardized Pre-drilled Openings: Openings are provided as needed for oil conservator bases, gas relay interfaces, high and low voltage riser bases, tap changer bases, drain valves, vent plugs, grounding terminals, sampling valves, and radiator interfaces. Ready for direct assembly upon delivery.
1. We can customize any of three structures based on customer drawings or existing fuel tanks through on-site measurement and replication;
2. We can provide a one-stop solution for supplying radiators, oil conservators, complete sets of sealing gaskets, and mounting bolts;
3. Each tank comes with an airtightness test report, meeting national standards GB1094, IEC, UL, ANSI, and other domestic and international certification requirements;
4. We offer rapid production scheduling for standard specifications, and controllable lead times for large-capacity high-pressure fuel tanks and American-style export fuel tanks. We also support OEM manufacturing for large-volume foreign trade orders.
